Sewing machine



April 26, 1955 s. R. BELL SEWING MACHINE Filed July 1v. 1952 INVENTOR [t 5| NEY R. BELL BY ATToRN Y United States Patent O SEWING MACHINE Sidney R. Bell, Stamford, Conn., assignor to Irving J. Moritt, Brooklyn, N. Y

Application July 17, 1952, Serial No. 299,395 13 Claims. (Cl. 112-193) This invention relates to sewing machines, and more particularly to a miniature, light-weight, electrically driven sewing machine.

The primary object of my invention is to generally improve sewing machines, especially small, light-weight sewing machines intended to be readily portable.

A more particular object of my invention is to generally improve the work feed and shuttle drive mechanism of sewing machines.

Still another object is to improve the sewing machine disclosed in my copending application Serial No. 85,191 filed April 2, 1949, since issued on July 6, 1954, as Patent No. 2,682,846. Many features of the present sewing machine are not claimed herein but are claimed in said copending application or in divisional or continuation-inpart applications thereof.

To accomplishthe foregoinggeneral objects, and other another, as are hereinafter more particularly described in the following specification. The specification is accompanied by a drawing in which:

Fig. 1 is a side elevation of a sewing machine embodying features of my invention;

Fig. 2 is a longitudinal section taken in elevation through the bed of the sewing machine;

Fig. 3 is a bottom plan view of the sewing machine with the bottom cover plate removed to expose the mechanism;

Fig. 4 is a detail showing a part of the feed plate lift mechanism, and is taken approximately in the plane of the line 4h4 of Fig. 2;

Fig. 5 is a section showing a detail, and taken approximately in the plane of the line 5 5 of Fig. 1; and

Fig. 6 is a partially sectioned fragmentary perspective explanatory of a detail.

Referring to the drawing, the sewing machine is shown in Fig. 1, it comprising an arm 12 overhanging a bed 14. The bed houses work feed and shuttle mechanism covered by a removable plate 16. The stitch length may be controlled by an adjustment indicated at 418. The direction of work feed may be reversed by a control handle indcated at 20. A bobbin from the shuttle may be rewound with thread from spool 24 by means of a shaft end projecting at 26. The machine is electrically driven, connection being made at 28 by means of a suitable plug, not shown, the connection preferably including a suitable speed control rheostat, not shown, arranged to be operated by either the knee or the foot, as described in my Patent No. 2,561,556 granted July 24, 1951.

The sewing machine head is preferably arranged to be carried in a small carrying case, not shown in the present drawing, but illustrated and described in my copending application Serial No. 40,917, filed July 27, 1948, since issued on May 4, 1954, as Patent No. 2,677,341. The sewing machine is readily portable and very tiny in dimension. To increase the work table area and to steady the machine, as described in said copending application, it is received in a mating opening in the case, which opening closely surrounds and comes liush with the top of the bed 14. To facilitate release of the then-surrounded needle plate 16, a pushbutton 30 is provided.

For the most part the sewing machine details are not described herein, being described in my aforesaid copending application Serial No. 85,191. The description there includes the main drive; the shuttle, the shuttle carrier and drive mechanism, and the relation between the shuttle and the needle 80 secured to reciprocable needle bar 66 by means of a thumbscrew 82; the thread tension mechanism centering about the parts 224 and 230; the bobbin wind mechanism utilizing the part 26; and the lamp and other miscellaneous details of the sewing machine.

The part 26 is the upper end of the drive shaft of a high speed electric motor disposed in upright position in the sewing machine head. The lower end of this shaft is shown at 26 in Figs. 2 and 3, and is geared through appropriate reduction gearing to a a worm gear 446 (Fig. 3) on pending application Serial No. 85,191. It is indicated here only to clarify the fact that the motions of the sewing machine, and more specifically the motion of the needle bar, the feed plate and the shuttle, are kept in properly timed relation because the motions all are taken from the same cam shaft, that is, shaft 442.

Referring now to Figs. 2 and 3 of the drawing, the shuttle drive is taken from a cam 462 carried at the lower end of the cam shaft 442 just above the helical gear 452. In Fig. 3 most of the helical gear 452 has been cut away to more clearly show the cam 462 and the cam follower surfaces 464 which cooperate therewith.

The surfaces 464 are formed in the enlarged rear end 466 of a shuttle drive lever 468 pivoted at 470. The forward end of shuttle drive lever 46S is toothed to form a gear sector 472. This meshes with a shuttle drive pinion 474 The pinion 474 is formed integrally with a shuttle shaft 476. The upper part of the shuttle shaft passes through the hub portion 478 of a shuttle carrier 480, and is permanently riveted to the shuttle carrier at its upper end. Thus the shuttle carrier 480, pinion 474, and shaft 476 may be dropped into place from above, and turn in unison.

The lower end of the shaft 476 receives a thrust washer 482 and the Whole assembly is held in place by a split snap ring 484 received in a groove in shaft 476.

It will be understood that the shuttle 172 is of the oscillating hook type, and that it rests loosely on top of the carrier so that a loop of thread from the needle can pass bodily around the shuttle. The shuttle carrier and shuttle are oscillated over an angle somewhat less than one revolution. The bobbin 174 rests loosely in a mating chamber in the shuttle 172. By depressing button 30 a lever 432 releases and raises the needle plate 16 which, when lifted, exposes the bobbin and shuttle, so that the bobbin is readily removed for rewinding or replacement. The detailed construction and inter-relation of the bobbin, the shuttle, the shuttle carrier, and the movement and timing of the hook on the shuttle relative to the eye of the needle 8), are all described in detail in my copending application Serial No. 85,191 previously referred to, and require no further description here except to say that rotation of the main vertical cam shaft 442 causes the feed cam 462 to oscillate the feed lever 46S and thus to oscillate the pinion 474 and shuttle carrier 480 and with it the shuttle 172, in proper time relation to the reciprocation of the needle bar 66.

The work to be sewn is fed by a vertical feed plate having a serrated upper edge 92 and additional serrated edges 94. This plate is slidably held by appropriate guide walls in the bed of the machine, which walls serve to hold the plate in erect position while affording both horizontal and vertical movement. The horizontal movement of the feed plate is obtained from a generally horizontal feed lever 96 (Fig. 3) pivoted at 98. The forward end of feed lever 96 engages the feed plate 90. More specifically, it is received in a vertical slot formed near one end of the feed plate, this vertical slot being useful to permit the vertical component f the four-way movement of the feed dog, and also to accommodate any slight vertical movement of lever 96 which may take place incidental to a feed reversing operation described later. The rectangular rear end 97 of feed lever 96 encloses either of two axially displaced feed cams 100 and 102. There are sloping transition surfaces between the two cams. The hollow rectangle is long enough to clear the cam, so that feed lever 96 is not moved longitudinally by the earn. However, the feed cam oscillates the feed lever 96 about the fulcrum point 98, with consequent horizontal movement of the work feed plate 90.

The necessary vertical movement of the feed plate is obtained from the shuttle drive mechanism. For this purpose the intermediate part of the shuttle drive shaft 476 has a fiat 486. This is received in the hub 488 of an eccentric 490. Referring now to Fig. 4 it will be seen that the eccentric 490 is received between bearing surfaces in a feed lift cam plate 492 which is disposed horizontally, and guided by guideways (not shown in Fig. 4) to permit movement longitudinally of the bed of the machine. This cam plate engages the feed plate 90, and has a sloping portion 494 which acts as a cam to raise or lower the feed plate. In the specific coristruction here shown the end of the cam plate is tapered or wedge-shaped, as shown at 494, in Figs, 2 and 4, and bears against the upper surface of a relatively long horizontal slot cut through the feed plate 90. This horizontal slot is longer than the width of the cam plate, so that the latter does not interfere with the desired horizontal or feed movement of feed plate 90 caused by feed lever 96, as previously described. Actually, in the present case the unnecessary bottom wall of the slot is eliminated, so that the cam plate bears against the bottom edge of the feed plate, which, however, is recessed upwardly.

The sliding cam plate 492 is held upwardly by an Oilite bottom plate 496 (Figs. 2 and 3). This has side edges or ways which guide the plate 492 in its longitudinal reciprocation. The Oilite molded piece 496 is held upwardly by three screws shown at 498 in Fig. 3. It has molded integrally therewith an upwardly directed offset part 500 (Fig. 3) which acts as a support for the forward end of the feed lever 96 previously referred to. It also has a depending cylindrical boss or bearing 502 which receives the hub 488 of the eccentric 490, and also receives the lower end of the shuttle drive shaft 476.

The feed plate 90 is normally held downward in engagement with the sloping portion 494 of the cam plate 492 by means of a spring wire 504. The free ends of the wire 504 are received in holes in the feed plate, and the center portion of the spring wire is coiled about the boss 502 and is held upward by means of a snap washer 506 which is pushed upwardly on boss 502, and which has radial, inwardly projecting lingers which grip on the boss.

It will be evident that the oscillation of the shuttle drive pinion 474 is accompanied by oscillation of the eccentric 490, which in turn reciprocates the cam plate 492, and so provides vertical movement for the feed plate 90. This is properly timed, in relation to the horizontal movement of the feed plate, by the relation between the cams on the main cam shaft 442.

The stitch length may be adjusted by shifting the position of the fulcrum point 98 longitudinally of the feed lever 96. In Fig. 3 it will be seen that there is a cylindrical block 510 oscillatable in an Oilite bearing 512. The cylindrical block 510 is slotted to receive the feed lever 96. The resulting legs straddling the lever 96 permit it to be raised or lowered. The bearing 512 is itself slidable longitudinally of the feed lever in ways 514 formed in the bed of the machine as cast. The bearing 512 is moved by a slide 520 controlled by the knob 418 previously referred to, and shown in Figs. l and 6. Knob 418 is a plastic piece passing through a slot 522 formed between the upper and lower castings of the sewing machine head. The inner portion of knob 41S carries the upper end of a vertical part 521 (Fig. 5) connected to or formed integrally with the slide 520 (Fig. 3). The latter is held upwardly by means of a spring piece 524 (Fig. 3). This piece is indented at 526, and acts as a detent cooperating with a Series of 4 mating detent holes 528 in the slide 520. Thus the slide may be moved in increments, and is self-locking by reason of the detents. These increments correspond to markings on a scale 530 (Fig. 1) above the slot 522.

Reverting to Fig. 5, it will be seen that the finger piece 418 has a slot 532 which fits over the upper edge 534 of the lower casting 14. In assembling the machine the finger piece may be placed downwardly over the edge 534 before adding the upper casting to the lower casting. The finger piece also has a pocket 536 which tightly receives the upper end of the slide part 521.

The feed reverse mechanism is controlled by knob 20 shown in Fig. l. As is more fully described in my copending application Serial No. 85,191, this serves to raise or lower a generally upright plate or connecting link, the horizontally slotted lower end of which is shown at 540 in Fig. 2 of the drawing. Link 540 is connected at 542 to the rearmost end of the feed lever 96, and may be used to raise or lower the feed lever, thus bringing it into engagement with either the feed cam 10i), or the feed cam 102. These cams are appropriately displaced rotationally to change the timing at the feed plate 9i), so that in one case the feed plate is in its elevated position during forward movement, thus causing forward movement of the material being sewn, and in the other case the feed plate is in its elevated position during rearward movement, thus causing rearward movement of the material being sewn.

The feed lever 96 is held against longitudinal movement by a rib (Fig. 6) fitting in a transverse groove 97. The location of the rib 95 is also shown in Fig. 3, and it will be noted that it is directly above the support 500 which supports the feed lever 96. The rib 95 is cast integrally with the main casting for the bed of the machine. It not only prevents endwise movement of the feed lever 96, but also acts as a fulcrum point for the feed lever when the rear end of the same is moved vertically to shift it from forward feed to reverse feed, or vice versa. This fulcrum is disposed very near the forward end of the lever, thus reducing to a minimum the up-anddown motion of the forward end of the lever in the feed plate 90.

Referring now to Fig. 2, the open bottom of the cast bed of the machine is closed by means of a sheet metal bottom plate 550, the periphery of which is preferably provided with a rubber pad 552. The periphery of the plate is received within the casting and rests on suitable projections or stop surfaces such as those indicated at 554, 556, 558 and 560. The plate is held upwardly in position by means of a screw 562. This may be received in the hexagonal head 470 of a bearing pin 564 having a threaded shank 566 screwed into a boss 568 cast integrally with the machine bed. A bearing washer 570 may be intei-posed, it being understood that when screw 566 is tightened there is still clearance for free oscillation of the shuttle drive lever 468. The head 470 is extended downward a sufficient distance to act as a mounting means against which the bottom plate 550 may be tightened by its single holding screw 562.

It is believed that the construction, operation, and method of use, as well as the advantages of my improved sewing machine, will be apparent from the foregoing detailed description. It will also be apparent that while I have shown and described the invention in a preferred form, changes may be made in the structure disclosed, without departing from the scope of the invention, as sought to be defined in the following claims.

I claim:

l. A sewing machine comprising a sewing machine arm carried over a bed, a vertical cam shaft near the rear portion of the arm, a needle bar near the forward portion of the arm, a cam on the upper portion of said carri shaft and a lever driven thereby to operate said needle bar, an oscillatable shuttle in the bed cairied by a shuttle carrier having a pinion, a horizontal shuttle drive lever in said bed, a shuttle drive cam on the lower portion of the aforesaid vertical cam shaft for oscillating said shuttle drive lever, and a gear sector at the forward end of said lever meshing with the aforesaid pinion to oscillate the shuttle.

2. A sewing machine comprising a bed, a cam shaft near the rear portion of the bed, an oscillatable shuttle in the bed carried by a shuttle carrier having a pinion, a shuttle drive lever in said bed, a shuttle drive earn on the aforesaid cam shaft for oscillating said shuttle drive lever, a gear sector at the forward end of said lever meshing with the aforesaid pinion to oscillate the shuttle, a vertia horizontal cam plate reciprocable longitudinally of the cal work feed plate carried in said bed and having a sermachine by said eccentric, and a part of said cam plate rated upper edge, guide walls in the bed for holding said engaging said feed plate and sloping to act as a lift cam. plate in erect position while affording horizontal and ver- 7. A sewing machine comprising a bed, a cam shaft tical movement thereof and a feed plate lift mechanism 5 near the iear portion of the bed, an oscillatable shuttle including a cam driven by the shuttle pinion and a means in the bed carried by a shuttle carrier having a pinion, riven by said cam and engaging said feed plate. a shuttle drive lever in said bed a shuttle drive cam on 3. A sewing machine comprising a sewing machine arm the aforesaid cam shaft for oscillating said shuttle drive carried over a bed, a vertical cam shaft near the rear porlever, a gear sector at the forward end of said lever tion of the arm, a needle bar near the forward portion of meshing with the aforesaid pinion to oscillate the shutthe arm, a cam on said cam shaft and a lever driven theretle, a vertical work feed plate carried in said bed and by to operate said needle bar, an oscillatable shuttle in aving a serrated upper edge, guide walls in the bed the bed carried by a shuttle carrier having a pinion, a for holding said plate in erect position while affording horizontal shuttle drive lever in said bed a shuttle drive horizontal and vertical movement thereof, a vertical cam on the aforesaid vertical cam shaft for oscillating said l5 slot in said plate a feed lever in said bed, a feed cam shuttle drive lever, a gear sector at the forward end of on the aforesaid cam shaft for engaging the rear end said lever meshing with the aforesaid pinion to oscillare of said feed lever the forward end of said feed lever the shuttle, a vertical work feed plate carried 1n said eing received in the vertical slot of the feed plate a bed and having a serrated upper edge, guide walls in the fulcrum located at an intermediate point on said feed bed for holding said plate in erect position while affording lever, means for shifting said fulcrum longitudinally of orizontal and vertical movement thereof a feed lift ecthe feed lever to vary the stitch length a feed lift eccentric rotated bythe shuttle pinion, ahoiizontal cam plate centric rotated by the shuttle pinion, a horizontal cam reciprocable longitudinally of the machine by said eccenplate reciprocable longitudinally of the machine by said tric, a part of said cam plate engaging said feed plate and eccentric and a part of said cam plate engaging said sloping to act as a lift cam, the cams on the aforesaid fe d plate and sloping to act as a lift cam vertical cam shaft being disposed in proper relation to Sewing machine comprising a Sewing machine PrOPerly time the n.lOtlOnS 0f the Ileedle bar, the feed Plate, arm carried over a bed a vertical cam shaft near the andthe shuttle carrier. l rear portion of the arm, a needle bar near the forward l 4. A sewing machine comprising a bed, a' vertical cam P01-tion of the arm, a cam on the upper portion 0f.said shaft near the rear portion of the bed, an oscillatablenshutcam shaft and a lever driven thereby to operate Said le Il the bed carried by a Shuttle carrler llaVlIlg a PIHIOH, needle bar, an oscillatable shuttle in the bed carried by a shuttle drive lever iii said bed a shuttle drive cam on the a shuttle carrier having a pinion, a horizontal shuttle aforesaid vertical cam shaft for oscillating said shuttle drive lever m Said bed, a shuttle dnve cam on the lower the aforesaid vertical carn shaft for oscillating Said Shllting said shuttle drive lever, a gear sector at the forward tle, a Vertical Werk feed Plate carrled ln Sald bed and end of said lever meshing with the aforesaid pinion aVlIlg a serrated uPPer edge, guide Wells 111 the bed fdr to oscillate the shuttle, a vertical work feed plate carhOldlIlg Sald Plate 111 erect POSltlOn Wlllle atlerdlng herlried in said bed and having a serrated upper edge guide zontal and vertical movement thereof, a feed lever in said walls in the bed for holding Said plate m erect posmon bed, a feed cam 0n the dferesald Vertlcal cem Shaft for 40 while atfording horizontal and vertical movement thereengaging tlle rear end Ofsald feed lever, the fOrWald end of, a vertical slot in said plate, a generally horizontal of said feed lever englaglrlg tlle feed Plate; a fulcrum l0* feed lever in said bed, forward and reverse feed cams cated at an intermediate point on said feed lever, and on the lower portion of the aforesaid Cam shaft for means for shifting said fulcrum longitudinally of the feed engaging the rear end of Said feed lever, the forward leVel' t0 Vall tlle Stltcll length' 45 end of said feed lever being received in the vertical slot SeWlIlg machine cOmPrlSlng a Sewlllg macllllle afm of the feed plate feed reverse means connected to said carried over a bed, a vertical cam shaft near the rear feed levelto false or lower 1t Into engagement with Pertlcn 0f the afm: a needle bal deal the forward Por either the forward oi reverse feed cam, a feed lift ectlOIl 0f the arm, e cam 0H the UPPel Pol'tldll 0f sald cam centric rotated by the shuttle pinion a horizontal cam Shaft and a lever drlVen thereby t0 Operate Sald needle 5d plate reciprocable longitudinally of the machine by said bar, an oscillatable shuttle in the bed carried by a shuttle eccenme a part of Sald cam plate engagmg Sald feed carrier having a pinion, a horizontal shuttle drive' lever,` plate an sloplng to act as a lllt cam, the cams on the 111 Said bed, a Shuttle dllVe Cam dll the lower Pollloll of aforesaid vertical cam shaft being disposed in proper the aforesaid vertical cam shaft for oscillating said shutrelatlon to properly time the motions Olthe needle bar tle drive lever, a geai sector at the foiward end of said 53 the feed plate and the shuttle carrier lever meshing with the aforesaid pinion to oscillate the A Sewng machine comprlslng'a Sewmg machme shuttle a vertical work feed plate carried in said bed arm' carmed over a bed a vertlcal cam shaft near the and havlllg d serrated upper edge gulde walls m the bed? rear portion of the arm, a needle bar near the forward horizontal and vertical movement thereof, a vertical slot (30 Operate .Said needle bar aniosciuafable Shuttle in the the rear portion of the bed, an oscillatable s huttle in the upper edge, guide walls m the bed for holdmg Saul plate to said feed lever to raise or lower it into engagement in erect position while affording horizontal and vertical S0 wltll eltllet' tlle forward 0r reVerSe feed cam a feed movement thereof a vertical slot in said plate, a feed lever llft eccenlrlc TOtated by the Shuttle PlnlOD a hOllZOntl in said bed, a feed cam on the aforesaid cam shaft for Cam Plate reclPrOcable longltlldlnally 0f the machine engaging the rear end of said feed lever, the forward end by Sald eccentric, a part of said cam plate engaging said of said lever being received in the vertical slot of the feed feed plate and sloping to act as a lift cam, the cams on plate, a feed lift eccentric rotated by the shuttle pinion, S5 the aforesaid vertical cam shaft being disposed in proper ing to act as a lift cam, the cams relation to properly time the motions of the needle bar, the feed plate, and the shuttle carrier.

10. A sewing machine comprising a sewing machine arm carried over a bed, a vertical cam shaft near the rear portion of the arm, a needle bar near the forward portion of the arm, a cam on the upper portion of said cam shaft and a lever driven thereby to operate said needle bar, an oscillatable shuttle in the bed carried by a shuttle carrier having a pinion, a horizontal shuttle drive lever in said bed, a shuttle drive cam on the lower portion of the aforesaid vertical cam shaft for oscillating said shuttle drive lever, a gear sector at the forward end of said lever meshing with the aforesaid pinion to oscillate the shuttle, a vertical work feed plate carried in said bed and having a serrated upper edge, guide walls in the bed for holding said plate in erect position while affording horizontal and vertical movement thereof, a ver tical slot in said plate, a generally horizontal feed lever in said bed, a feed cam on the lower portion of the aforesaid carn shaft for engaging the rear end of said feed lever, the forward end of said feed lever being received in the vertical slot of the feed plate, a feed lift eccentric rotated by the shuttle pinion, a horizontal cam plate reciprocable longitudinally of the machine by said eccentric, a part of said cam plate engaging said feed plate and sloping to act as a lift cam, the cams on the aforesaid vertical cam shaft being disposed in proper relation to properly time the motions of the needle bar, the feed plate, and the shuttle carrier.

ll. A sewing machine comprising a sewing machine arm carried over a bed, a vertical cam shaft near the rear portion of the arm, an oscillatable shuttle in the bed carried by a shuttle carrier having a pinion, a horizontal shuttle drive lever in said bed, a shuttle drive cam on the lower portion of the aforesaid vertical cam shaft for oscillating said shuttle drive lever, a gear sector at the forward end of said lever meshing with the aforesaid pinion to oscillate the shuttle, a vertical work feed plate carried in said bed and having a serrated upper edge, guide walls in the bed for holding said plate in erect position while affording horizontal and vertical movement thereof, a vertical slot in said plate, a generally horizontal feed lever in said bed, forward and reverse feed cams on the lower portion of the aforesaid cam shaft for engaging the rear end of said feed lever, the forward end of said feed lever being received in the vertical slot of the feed plate, feed reverse means connected to said feed lever to raise or lower it into engagement with either the forward or reverse feed cam, a feed lift eccentric rotated by the shuttle pinion, a horizontal cam plate reciprocable longitudinally of the machine by said eccentric, a part of said cam plate engaging said feed plate and slopon the aforesaid vertical cam shaft being disposed in proper relation to properly time the motions of the needle bar, the feed plate, and thc shuttle carrier.

l2. A sewing machine comprising a sewing machine arm carried over a bed, a vertical cam shaft near the rear portion of the arm, a needle bar near the forward portion of the arm, a cam on the upper portion of said cam shaft and a lever driven thereby to operate said needle bar, an oscillatable shuttle in the bed carried by a shuttle carrier having a pinion, a horizontal shuttle drive lever in said bed, a shuttle drive cam on the lower ortion of the aforesaid vertical cam shaft for oscillating said shuttle drive lever, a gear sector at the forward end of said lever meshing with the aforesaid pinion to oscillate the shuttle, a vertical work feed plate carried in said bed and having a serrated upper edge, guide walls in the bed for holding said plate in erect position while affording horizontal and vertical movement thereof, a vertical slot in said plate, a generally horizontal feed lever in said bed, a feed cam on the lower portion of the aforesaid cam shaft for engaging the rear end of said feed lever, the forward end of said feed lever being received in the vertical slot of the feed plate, a fulcrum located at an intermediate point on said feed lever, and means for shifting said fulcrurn longitudinally of the feed lever to vary the stitch length.

13. A sewing machine comprising a sewing machine arm carried over a bed, a vertical cam shaft near the rear portion of the arm, an oscillatable shuttle in the bed carried by a shuttle carrier having a pinion, a horizontal shuttle drive lever in said bed, a shuttle drive cam on the lower portion of the aforesaid vertical cam shaft for oscillating said shuttle drive lever, a gear sector at the forward end of said lever meshing with the aforesaid pinion to oscillate the shuttle, a vertical work feed plate carried in said bed and having a serrated upper edge, guide walls in the bed for holding said plate in erect position while affording horizontal and vertical movement thereof, a vertical slot in said plate, a generally horizontal feed lever in said bed, forward and reverse feed cams on the lower portion of the aforesaid cam shaft for engaging the rear end of said feed lever, the forward end of said feed lever being received in the vertical slot of the feed plate, a fulcrum located at an intermediate point on said feed lever, means for shifting said fulcrum longitudinally of the feed lever to vary the stitch length, and feed reverse means connected to said feed lever to raise or lower it into engagement with either the forward or reverse feed cam.

References Cited in the tile of this patent UNITED STATES PATENTS 

